YOU SAID:

old people were young people before young people were people

INTO JAPANESE

老人は若者であり、若者は若者でした

BACK INTO ENGLISH

The old man was a young man and the young man was a young man

INTO JAPANESE

老人は若い男で、若い男は若い男でした

BACK INTO ENGLISH

The old man was a young man and the young man was a young man